When I got my Airstream I knew it wouldn't be long before I added curtains to the windows that only had roll-down shades. The shades are nice but they leave gaps at the edges. My mother enjoys sewing and was happy to take on the challenge. The front pano curtains were made just like the ones from the factory and were more difficult than the others because they aren't just rectangular pieces of fabric. There are some deliberate curves in the lines to allow them to track correctly across the front.
The side and rear windows were much easier. All curtains were made with a blackout backing to keep the interior as dark as possible -- even when the neighbors leave the scare light on all night.
The blackout lining has also helped to keep the interior cooler, too.
I had to purchase extra curtain track from my dealer along with the mounting brackets. The hardware to do the two side windows and the two bedroom windows was maybe $45. Pretty reasonable, really. Installation was easy using only a drill, screwdriver, and tape measure.
The fabric came from fabricguru.com and was an end-of-the-roll remnant but still first quality. It was labeled as "famous maker outdoor" which sounds like Sunbrella or something equivalent. It's very sturdy and I'm hoping it will not suffer too much from the effects of UV.
The addition of some color and pattern added some life to the interior. Overall, I'm very happy with the update.